Father Grumpmas:
Mars Ultor has the ARRASADORES DEL APOCALIPSIS in their Chaos section - these guys could double as Bull Centaurs - they do have a mask thing going on rather than a big hat.
http://www.marsultor.com/catalogo.php?jid=1&eid=2
The Dwarf section contains a great figure to use as a Kolossus, assuming that is a 40x40mm (or bigger!) base it is pictured on
https://discourse.chaos-dwarfs.com/t/5508
The Grendel Leviathan range also has some Kolossus style figures
http://www.scotiagrendel.com/grendel.html